<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="../js/react.development.js"></script>
    <script src="../js/react-dom.development.js"></script>
    <script src="../js/babel.min.js"></script>
    <script src="../js/prop-types.js"></script>
</head>
<body>
    <div id="root"></div>
    <script type="text/babel">
        class Welcome extends React.Component {
            constructor(props) {
                super(props);
                this.state = {
                    content: '',
                }
            }
            readContent = (event) => {
                this.setState({
                    content: event.target.value,
                })
            }
            render() {
                return (
                    <div>
                        <textarea content={this.state.content} onChange={this.readContent}/>
                        {this.state.content && (
                            <h2>you have input: {this.state.content}</h2>
                        )}
                        {this.props.value ? (
                            <h2>{this.props.value}</h2>
                        ) : (
                            <h2>请传入value</h2>
                        )}
                    </div>
                )
            }
        }
        ReactDOM.render(<Welcome value={123}/>, document.getElementById('root'));
    </script>
</body>
</html>